Porterbrook Cl.769 'Flex' trains from 319s, initially for Northern

[Peter Sarf]

Here is the CAF webpage extolling the flexibility of their design and the options that it can offer customers:
https://www.caf.net/en/productos-servicios/familia/civity/modularidad.php
on this page is a list of types currently available*:

........
Civity platform includes trains with different types of traction based on a single concept of a modular, low-floor vehicle. Civity trains are available with the following types of traction:

• Electric (EMU)
• Diesel-mechanical or diesel-hydraulic (DMU)
• Diesel-electric (DEMU)
• Bi-mode (BMU)

EMUs WITH BATTERIES
Civity trains with all types of traction can be equipped with batteries. These can be used to move the train without external power supply or to provide extra power to the train when there is a limitation in the catenary power. Batteries can also enable energy storage during braking reducing energy consumption.

CAF energy storage systems are modular and configurable, making them easily adaptable to requirements of each customer.
........

It is clear that they already have the ability to supply a DEMU, and a BI-Mode (EDMU), and can fit batteries to EMUs. Given the current rate of development of a multi-mode market for multiple unit trains, I can't believe that CAF wouldn't accept orders for EDMUs now with an option for upgrading by fitting batteries in the not too distant future. In addition, once a MU is supplied with electric motor bogies (as with EDMU and DEMU configurations) there is minimal redundancy of hardware when fitting out to EDMU + batteries or even BEMU, (by removing the diesel gensets). Thus I can only guess that the rush to buy straight DMUs that would be in polluting service beyond even the least ambitious cut-off date for hydrocarbon road vehicle sales is an ill-considered myopic response to the poor performance of the Northern franchise.

* Although those types of MUs are advertised, there would of course be some development to fit a DEMU in a UK loading gauge configuration, but the modularity of the series has been amply demonstrated by deliveries elsewhere, with both low and normal (for us) floor heights. Such a design would only need to accomodate the transformer/converter and some additional cabling/switchgear.

Wait a minute - in the above you quote from CAF
1) CAF are saying there that their "Diesel-mechanical or diesel-hydraulic (DMU)" can be fitted with batteries !.
2) And that catenery power is relevant !.
Pinch of salt time ?.

I would love someone from DfT to explain the rationale behind ordering the 195s with mechanical transmission, with no obvious route for conversion to bi-mode or battery operation. I just can't get my head around it - why would you do such a thing? About the only reason I can think of is cost - but even then, it's not a cheap option viewed over expected lifespan of the trains, as retro-fitting the capability for bi-mode or battery operation will cost a pretty penny. The other option would be to replace the 195s with a less environmentally harmful product mid-way through their expected lives - also not cheap.

However, I suspect that whoever made this short-sighted decision will not be held to account.

Meanwhile, residents of Northern towns and cities will continue to suffer emissions for years to come. There's already a significant difference in life expectancy and health profiles of the north and the south, and the 195s are set to play their part in perpetuating - or even increasing it.

I don't think that DaFT chose the actual units but their outline requirements and how they chose a new Train Operating Company will certainly have influenced things.

As for pollution and its affects on health. I think rail generated pollution is a lot less significant per passenger than road pollution. Therefore the railways should be allowed to help reduce road traffic without worrying too much about rail pollution. But at the end of the day electrification is appropriate where there is significant enough traffic.

The levels of pollution in Greater London have got to be far worse than in smaller conurbations like Birmingham and Manchester. Certainly since the rise of smokeless zones. I seem to recall that life expectancy has more to do with lifestyle (diet, smoking or maybe nature of work). Here in Croydon (3rd rail land) the A23 near me is classed as at illegal pollution levels !. I can even smell the pollution when I come back from Cardiff but after a short while I am used to it .

I am one of those who thinks, where the rail traffic is high enough, electrification is necessary. The 769s gave an opportunity to electrify the busiest parts of routes whilst not causing the need for people to change into another train at the point where the wiring ended. The route onwards not being busy enough to justify electrification (yet). How this should manifest itself is as diesel trains from outlying areas that can use the electrification in the suburbs. Sadly the railway manufacturing industry appears to be failing to deliver that solution. Perhaps a purpose built Bimode is better but there are an awful lot of reasonable EMUs going spare that could be converted !.

 

[AM9]

Wait a minute - in the above you quote from CAF
1) CAF are saying there that their "Diesel-mechanical or diesel-hydraulic (DMU)" can be fitted with batteries !.
2) And that catenery power is relevant !.
Pinch of salt time ?. ...

Not sure what you are getting at there.

 

[Peter Sarf]

Not sure what you are getting at there.

Sorry, I was wondering, in the text you quoted from CAF. Surely a diesel mechanical unit or diesel hydraulic unit is unlikely to be able to use batteries for traction power ?. I then also noted CAF talking about catenery - surely not applicable to any non-BiMode diesel multiple unit ?. I highlighted the bits that concerned me in red but neglected to say I did that .

 

[krus_aragon]

Sorry, I was wondering, in the text you quoted from CAF. Surely a diesel mechanical unit or diesel hydraulic unit is unlikely to be able to use batteries for traction power ?. I then also noted CAF talking about catenery - surely not applicable to any non-BiMode diesel multiple unit ?. I highlighted the bits that concerned me in red but neglected to say I did that .

The first portion you highlighted was under the header:

EMUs WITH BATTERIES
Civity trains with all types of traction can be equipped with batteries

So is the original document actually trying to say that all types of electric traction can be equipped with batteries?

 

[Energy]

The first portion you highlighted was under the header:

So is the original document actually trying to say that all types of electric traction can be equipped with batteries?

Think so, I think what it meant all EMUs/BMUs/DEMUs could be fitted with batteries as they are all forms of EMUs.

 

[Peter Sarf]

The first portion you highlighted was under the header:

So is the original document actually trying to say that all types of electric traction can be equipped with batteries?

Mmm. I am not sure anymore !. Maybe I am interpreting it wrong.

I was reading it as all types of Civity so all four in the list above. which would include DMUs. Which made me suspicious.

But as you say it is under a heading of EMUs with batteries. So does it mean just EMUs ?.

Common sense says it could mean batteries for EMUs/BMUs/DEMUs.

Think so, I think what it meant all EMUs/BMUs/DEMUs could be fitted with batteries as they are all forms of EMUs.

Common sense says batteries for EMUs/BMUs/DEMUs. Of course the limitation for BMU/DEMUs would be if the engines are occupying the space where batteries would go. Nothing to say that the engines would not be removed. In an ideal world a BMU/DEMU could be converted at the time in the units life that the diesel engine was worn out. Which would coincide with significant parts of some routes getting electrified. So that won't work .

 

[edwin_m]

Mmm. I am not sure anymore !. Maybe I am interpreting it wrong.

I was reading it as all types of Civity so all four in the list above. which would include DMUs.

But as you say it is under a heading of EMUs with batteries. So does it mean just EMUs ?.

Common sense says batteries for EMUs/BMUs/DEMUs or at least the first two.

Maybe something like what Chiltern have done to hybridise their DMUs?

 

[AM9]

Mmm. I am not sure anymore !. Maybe I am interpreting it wrong.

I was reading it as all types of Civity so all four in the list above. which would include DMUs.

But as you say it is under a heading of EMUs with batteries. So does it mean just EMUs ?.

Common sense says batteries for EMUs/BMUs/DEMUs or at least the first two.

Actually, if there was sufficient space for batteries, it would make a very flexible unit: in DEMU mode, the kinetic energy could be recovered on braking and reused to enhance acceleration performance. In electric mode, batteries could be charged either from braking or from the OLE, -that power then being availble for short unenergised lengths of catenary, avoiding starting up the genset's from cold. Then there is the slow movements within yards and or hotel power when parked in a non-wired station.

 

[Peter Sarf]

Maybe something like what Chiltern have done to hybridise their DMUs?

I must find out more about that. Occurs to me that the only Battery units currently for service are the tube stock - so ex DC. And the 769s are borne out of 319s which are DC EMUS so something could be imminent there.

I see it as 319s converted with :-
1) Diesel for longer stretches away from electrification (current 769s).
2) Batteries instead for short non-electric sections.

This points to the need for electric traction motors - common sense.
Also a DC bus to handle battery power (D78s and 319s).

EDIT :- AM9 - you beat me to it !.

Actually, if there was sufficient space for batteries, it would make a very flexible unit: in DEMU mode, the kinetic energy could be recovered on braking and reused to enhance acceleration performance. In electric mode, batteries could be charged either from braking or from the OLE, -that power then being availble for short unenergised lengths of catenary, avoiding starting up the genset's from cold. Then there is the slow movements within yards and or hotel power when parked in a non-wired station.

You make me think. If no room under the floor then taking part of the passenger compartment in a 769 would be possible. It would not be noisy and the shape could be tall and thin to suit the passenger compartment unlike a horizontal engine (also hot, oily and exhaust).

BUT - Thumper anyone ? .

 

[D365]

I must find out more about that.

I was planning to attend an IET talk on the Chiltern hybridisation project last week, which inevitably ended up being cancelled. Otherwise I might have had some knowledge to share!

 

[Greybeard33]

I see it as 319s converted with :-
1) Diesel for longer stretches away from electrification (current 769s).
2) Batteries instead for short non-electric sections.

This points to the need for electric traction motors - common sense.
Also a DC bus to handle battery power (D78s and 319s).

319s have old fashioned DC commutator traction motors that are relatively inefficient compared with modern AC traction packages. Crucially, they are incapable of regenerative braking. This is relatively unimportant on the 769, where there is plenty of power from the diesel generators and nowhere to store regenerated energy. But it makes the 319 a non-starter for conversion to a battery unit, for which regenerative braking is vital to get reasonable range.

The battery 230s have had the original DC motors replaced by new AC motors.

Given the age of the 319s, re-tractioning is unlikely to be a viable option compared with battery conversion of a more modern EMU that already has AC traction motors.

 

[edwin_m]

319s have old fashioned DC commutator traction motors that are relatively inefficient compared with modern AC traction packages. Crucially, they are incapable of regenerative braking. This is relatively unimportant on the 769, where there is plenty of power from the diesel generators and nowhere to store regenerated energy. But it makes the 319 a non-starter for conversion to a battery unit, for which regenerative braking is vital to get reasonable range.

Regeneration is theoretically possible with DC motors - the Woodhead locos used to have it - but I agree that to provide regeneration on these units would involve a lot of changes that wouldn't be worth doing given their age. If the DC motors were kept the regeneration would be less effective than with AC motors.

Given the age of the 319s, re-tractioning is unlikely to be a viable option compared with battery conversion of a more modern EMU that already has AC traction motors.

Probably one reason why the 350s are being suggested as a battery hybrid unit.

The battery and the diesel engine are essentially doing the same thing when fitted to an EMU - giving it a capability to operate on non-electrified lines. So although fitting a battery (large enough to provide traction for a useful distance) as well as a diesel engine would result in a more efficient unit overall, spending the same amount fitting a similar battery to an EMU without a diesel engine would most likely deliver more benefit. There's also the question of where to put all this hardware. There's not much underfloor space left on a 769, and although taking passenger space might be OK on a rural branch line it's not ideal for something that regularly visits central Manchester. ​

 

[61653 HTAFC]

Using up just the space behind one or both cabs on a four car unit would be no great loss on many routes. Still over three and a half cars of passenger space there. Compare that to a pair of 150s and the space lost to the inner cabs, particularly if one or both of those 150s is an ungangwayed example, and there's not a whole lot in it.

Had Manchester got its wish ~35 years ago, units like that would have been the mainstay of GM commuter routes up to today.

 

[Meerkat]

I would love someone from DfT to explain the rationale behind ordering the 195s with mechanical transmission, with no obvious route for conversion to bi-mode or battery operation

I assumed they were ordered before the dates pressure and when confidence in batteries was low, with the intention they ended their lives pottering on the rural branchlines that are very unlikely to be electrified - hence only being 2 cars.

 

[samuelmorris]

319s have old fashioned DC commutator traction motors that are relatively inefficient compared with modern AC traction packages. Crucially, they are incapable of regenerative braking. This is relatively unimportant on the 769, where there is plenty of power from the diesel generators and nowhere to store regenerated energy. But it makes the 319 a non-starter for conversion to a battery unit, for which regenerative braking is vital to get reasonable range.

The battery 230s have had the original DC motors replaced by new AC motors.

Given the age of the 319s, re-tractioning is unlikely to be a viable option compared with battery conversion of a more modern EMU that already has AC traction motors.

Why is that? Older tube stock has/had rheostatic braking with DC motors, and if you can have rheostatic braking I don't see why you can't have regenerative?

 

[plugwash]

I think it's not so much about the motors as about the power electronics.

You could build power electronics that would take the power generated by a DC motor and boost it's voltage up to feed it back into the batteries, but by the time you have gone to the effort/expense of doing that you may as well just replace the whole damn traction package with a modern variable frequency drive system and AC motors.

 

[Energy]

Maybe something like what Chiltern have done to hybridise their DMUs?

Unfortunately the Chiltern hybrids seem to be slow progress.

 

[Greybeard33]

Why is that? Older tube stock has/had rheostatic braking with DC motors, and if you can have rheostatic braking I don't see why you can't have regenerative?

Yes, series wound DC motors can be designed so that they can work as generators to provide braking, but to do that you have to reverse the polarity of the field winding. That means bringing extra connections out of the motor and installing extra contactors to switch between motor and generator modes. I believe the 319 traction motors have the field hardwired internally and I doubt that it would be viable to modify them.

 

[plugwash]

Don't you have to be able to reverse the field winding on a series powered motor to reverse direction?

 

[AM9]

I think that there is a pressing case for all multiple units to have an electric traction DC bus, whatever the most efficient motors are, currently ac induction motors moving towards slightly lighter permanent magnet designs, managed by contemporary best-practice traction electronics. Onto that bus , all of the power options hang: pantograph/transformer/rectifier, diesel genset, batteries and 3rd rail shoes.

Yes, series wound DC motors can be designed so that they can work as generators to provide braking, but to do that you have to reverse the polarity of the field winding. That means bringing extra connections out of the motor and installing extra contactors to switch between motor and generator modes. I believe the 319 traction motors have the field hardwired internally and I doubt that it would be viable to modify them.

But the 319s already have rheostatic braking down to about 20mph. Reversing the polarity before it was applied to the batteries wouldn't be that difficult, even if there wasn't the full electronic voltage boost to step the lower speed voltage high enough to get a decent charge. Full regen back to the OLE or even the 3rd rail would be more complex, but having batteries would provide some short-term power boost that would help acceleration in some circumstances.
I'm not actually saying that the 769s should have batteries added, but functionally, the basic hardware is already there.

 

[Llama]

319s don't have rheostatic braking, I am sure of that one.

 

[D365]

319s don't have rheostatic braking, I am sure of that one.

Indeed, you’d hear it if they did.

 

[samuelmorris]

I can't say I've ever heard it myself.

 

[AndrewE]

Indeed, you’d hear it if they did.

Why would you? Cooling fans?

 

[D365]

Why would you? Cooling fans?

No, you’d be hearing the motors. However I’m not actually sure how many DC motored EMUs, if any, operate rheostatic braking.

 

[Tynwald]

313, 507, 508 certainly do. 314, 315, 317 etc don't.

 

[Domh245]

313, 507, 508 certainly do. 314, 315, 317 etc don't.

+ most DC motored tube stock, since the 67TS at least

 

[aleggatta]

313, 507, 508 certainly do. 314, 315, 317 etc don't.

313s now no longer operate it, since all the GN ones went to scrap, the SN ones never had it operational as it was isolated before the units came down south.

 

[AM9]

319s don't have rheostatic braking, I am sure of that one.

I could be wrong but I have a memory of a thread where a driver on Thameslink said that ER braking could be heard down to about 20mph with mechanical brakes taking over to standstill.

 

[Llama]

As far as I know they've never had rheostatic braking, I'm pretty sure that's the case, it certainly is now and there's no evidence there's been any equipment for it on any unit I've seen. I suppose it's possible that there might've been an experimental trial on a unit but there would need to be so many modifications it'd have been obvious.